Diester-based engine oil formulations with improved low noack and cold flow properties

ABSTRACT

The present invention is generally directed to diester-based multi-grade engine oil formulations. The diesters employed have a number a performance benefits in lubricant applications—among them: biodegradability, extreme temperature performance, oxidative stability, solubility for additives and deposit and sludge precursors, flash and fire points. However, ester usage in lubricants has been quite limited due to their high cost. We utilize new proprietary diesters, structurally different from traditional diesters, which are made from fatty acids and alpha olefins in simple processing steps, yet feature performance similar to more traditional lubricant esters.

FIELD OF THE INVENTION

The present invention relates to a multi-grade engine oils formulated tomeet the specifications for SAE viscosity grade 0W-XX or 5W-XX engineoil, wherein XX represents the integer 16, 20, 30, or 40. Formulationsmeeting the specifications for SAE viscosity grade 0W-20 and 5W-20 havebeen successfully prepared using the present invention. This desiredproperties achieved include multi-grade 0W-20 and 5W-20 SAE motor oilswith low Noack and excellent cold flow properties.

BACKGROUND OF THE INVENTION

Esters have been used as lubricating oils for over 50 years. They areused in a variety of applications ranging from jet engines,refrigeration and motor oils. In fact, esters were the first syntheticcrankcase motor oils in automotive applications. However, esters gaveway to polyalphaolefins (PAOs) due to the lower cost of PAOs and theirformulation similarities to mineral oils. In full synthetic motor oils,however, esters are almost always used in combination with PAOs tobalance the effect on seals, additives solubility, volatility reduction,and energy efficiency improvement by enhanced lubricity. In this aspect,novel diester-based multi-grade engine oil compositions comprising PAOshave been described in commonly-assigned U.S. patent application Ser.No. 12/548,191; filed Aug. 26, 2009.

Ester-based lubricants, in general, have excellent lubricationproperties due to the polarity of the ester molecules of which they arecomprised. The polar ester groups of such molecules adhere topositively-charged metal surfaces creating protective films which slowdown the wear and tear of the metal surfaces. Such lubricants are lessvolatile than the traditional lubricants and tend to have much higherflash points and much lower vapor pressures. Ester lubricants areexcellent solvents and dispersants, and can readily solvate and dispersethe degradation by-products of oils. Therefore, they greatly reducesludge buildup. While ester lubricants are stable to thermal andoxidative processes, the ester functionalities give microbes a handle todo their biodegrading more efficiently and more effectively than theirmineral oil-based analogues. Therefore, there exists an opportunity toemploy an alternative blending component that reduces volatility at areduced cost and with other advantages not afforded with PAO.

In view of the foregoing, a simpler, more efficient method of generatingdiester-based multi-grade engine oils would be extremely useful,particularly wherein such methods utilize renewable raw materials incombination with converting low value Fischer-Tropsch (FT) olefins andalcohols to high value diester base oils.

Novel diester-based lubricant compositions and their correspondingsyntheses have been described in commonly-assigned U.S. Pat. No.7,871,967 B2; issued Jan. 18, 2011. The synthetic routes described inthis patent application comprise and/or generally proceed through thefollowing sequence of reaction steps: (1) epoxidation of an olefin toform an epoxide; (2) conversion of the epoxide to form a diol; and (3)esterification of the diol to form a diester.

Moreover, novel diester-based lubricant compositions and theircorresponding syntheses have been described in commonly-assigned U.S.Pat. No. 7,867,959 B2; issued Jan. 11, 2011. The synthetic routesdescribed in this patent application comprise and/or generally proceedthrough the following sequence of reaction steps: (1) epoxidation of anolefin to form an epoxide; (2) directly esterifying the epoxide with acarboxylic acid to form a diester species.

Numerous governing organizations, including Original EquipmentManufacturers (OEM's), the American Petroleum Institute (API),Association des Consructeurs d' Automobiles (ACEA), the American Societyof Testing and Materials (ASTM), International Lubricant Standardizationand Approval Committee (ILSAC), and the Society of Automotive Engineers(SAE), among others, define the specifications for lubricating base oilsand engine oils. Increasingly, the specifications for engine oils arecalling for products with excellent low temperature properties, highoxidation stability, and low volatility. Currently, only a smallfraction of the base oils manufactured today are able to meet thesedemanding specifications.

Engine oils are finished crankcase lubricants intended for use inautomobile engines and diesel engines and consist of two generalcomponents (i.e., a lubricating base oil and additives). Lubricatingbase oil is the major constituent in these finished lubricants andcontributes significantly to the properties of the engine oil.Accordingly, there is need for Multi-grade engine oils formulatedlubricating oils, which have improved low volatility, excellent coldflow properties and improved fuel economy to meet today's stringentperformance requirements. The minimum specifications for the variousviscosity grades of engine oils is established by SAE J300 standards asrevised in January 2009.

SUMMARY OF THE INVENTION

In one embodiment, the present invention is directed to a multi-gradeengine oil comprising: a) a diester component, comprising a quantity ofat least one diester species having the following Formula I:

wherein R₁, R₂, R₃ and R₄ are the same or independently selected from C₂to C₁₇ hydrocarbon groups;

b) a second base oil; and

c) an additive package,

wherein the second base is selected from the group consisting of Group Ibase oil, Group II base oil or Group III base oil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart illustrates the Noack and CCS Viscosity of thediesters of the present invention as compared to the current commercialesters as presented in Table 6 and other Group II and III bases oils.

DETAILED DESCRIPTION OF THE INVENTION

In some embodiments, the present invention is directed to a multi-gradeengine oil comprising: a) a diester component, comprising a quantity ofat least one diester species of Formula I, wherein R₁, R₂, R₃ and R₄ arethe same or independently selected from C₂ to C₁₇ hydrocarbon groups; b)a second base oil; and c) an additive package, wherein the second baseis selected from the group consisting of Group I base oil, Group II baseoil or Group III base oil.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein a quantity of at least one diester species comprisesa mixture of isomers where R₁ and R₂ are different for each isomer.

In some embodiments, the present invention is directed to a multi-gradeengine oil, further comprising, a third base oil.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the diester has a Noack Volatility between about 6and 10 wt %, a CCS Viscosity at −30° C. between about 700 and 2000 cP, apour point less than about −10° C., a cloud point less than about −10°C., a kinematic viscosity at 100° C. between about 2.5 to 6.5centistokes, a VI greater than about 110 and a BN Oxidator greater thanabout 20 hours.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the diester has a Noack Volatility between about 6and 9 wt %, and a CCS Viscosity at −30° C. between about 800 and 1900cP.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the diester has a Noack Volatility between about 6and 9 wt %, and a CCS Viscosity at −25° C. between about 400 and 1250cP.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the second base and third base oil are independentlyselected from the group consisting of light neutral base oil, mediumneutral base oil, Yubase 4, Yubase 6, 150R, 600R, 110RLV, 220R and 100R.

In some embodiments, the present invention is directed to a multi-gradeengine oil, meeting the specifications for SAE viscosity grade 0W-XX or5W-XX, wherein XX represents the integer 16, 20, 30, or 40.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the multi-grade engine oil meets the SAE J300standards as revised in January 2009.

In some embodiments, the present invention is directed to a multi-gradeengine oil, having: a) a viscosity index between about 140-200; b) akinematic viscosity at 100° C. between about 6-10 cSt; c) a Pour Pointless than about −30° C.; and d) a Noack volatility of less than about 15wt %, wherein the multi-grade engine oil is a 0W-SAE grade with a CCSViscosity at −35° C. less than about 6200 cP or the multi-grade engineoil is a 5W-SAE grade with a CCS Viscosity at −30° C. less than about6600 cP.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the kinematic viscosity of the multi-grade engineoil at a temperature of 100° C. is between about 3 to 10 centistokes.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the CCS Viscosity at −30° C. less than about 6,600cP.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the CCS Viscosity at −35° C. less than about 6,200cP.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the Noack Volatility less than about 15 wt %.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein R₁ and R₂ are selected to have a combined carbonnumber of from 6 to 16 and R₃ and R₄ are selected to have a combinedcarbon number of from 10 to 34.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein R₁ and R₂ of Formula I are selected to have acombined carbon number of C₁₆, C₁₄ or C₁₂ and R₃ and R₄ areindependently selected from the group consisting of C₁₂ and a mixture ofC₆-C₁₀.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the at least one diester species is derived from aC₈ to C₁₈ olefin and a C₆ to C₁₄ carboxylic acid.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein said composition comprises quantities of at leasttwo different diester isomers.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the at least one diester species has a molecularmass that is from at least about 340 a.m.u. to at most about 780 a.m.u.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the at least one diester species is selected fromthe group consisting of decanoic acid 2-decanoyloxy-1-hexyl-octyl esterand its isomers, tetradecanoic acid-1-hexyl-2-tetradecanoyloxy-octylesters and its isomers, dodecanoic acid 2-dodecanoyloxy-1-hexyl-octylester and its isomers, hexanoic acid 2-hexanoyloxy-1-hexy-octyl esterand its isomers, octanoic acid 2-octanoyloxy-1-hexyl-octyl ester and itsisomers, hexanoic acid 2-hexanoyloxy-1-pentyl-heptyl ester and isomers,octanoic acid 2-octanoyloxy-1-pentyl-heptyl ester and isomers, decanoicacid 2-decanoyloxy-1-pentyl-heptyl ester and isomers, decanoicacid-2-cecanoyloxy-1-pentyl-heptyl ester and its isomers, dodecanoicacid-2-dodecanoyloxy-1-pentyl-heptyl ester and isomers, tetradecanoicacid 1-penty-2-tetradecanoyloxy-heptyl ester and isomers, tetradecanoicacid 1-butyl-2-tetradecanoyloxy-hexy ester and isomers, dodecanoicacid-1-butyl-2-dodecanoyloxy-hexyl ester and isomers, decanoic acid1-butyl-2-decanoyloxy-hexyl ester and isomers, octanoic acid1-butyl-2-octanoyloxy-hexyl ester and isomers, hexanoic acid1-butyl-2-hexanoyloxy-hexyl ester and isomers, tetradecanoic acid1-propyl-2-tetradecanoyloxy-pentyl ester and isomers, dodecanoic acid2-dodecanoyloxy-1-propyl-pentyl ester and isomers, decanoic acid2-decanoyloxy-1-propyl-pentyl ester and isomers, octanoic acid1-2-octanoyloxy-1-propyl-pentyl ester and isomers, hexanoic acid2-hexanoyloxy-1-propyl-pentyl ester and isomers, and mixtures thereof.

In some embodiments, the present invention is directed to a multi-gradeengine oil, wherein the multi-grade engine oil is formulated as a 0W-20SAE 0W-16 or 5W-20 SAE engine oil.

I. Engine Oil Composition

Base oils are the most important component of lubricant compositions,generally comprising greater than 70% of the lubricant compositions.Lubricant compositions comprise a base oil and at least one additive.Lubricant compositions can be used in automobiles, diesel engines,axles, transmissions, and industrial applications. Lubricantcompositions must meet the specifications for their intended applicationas defined by the concerned governing organization.

Additives, which can be blended with the base oil, to provide alubricant composition include those which are intended to improve selectproperties of the lubricant composition. Typical additives include, forexample, anti-wear additives, extreme pressure agents, detergents (e.g.,metal-containing detergents), dispersants (e.g., ashless dispersants),antioxidants, pour point depressants, VI Improvers (VII), viscositymodifiers, friction modifiers, demulsifiers, antifoaming agents,inhibitors (e.g., corrosion inhibitors, rust inhibitors, etc.), sealswell agents, emulsifiers, wetting agents, lubricity improvers, metaldeactivators, gelling agents, tackiness agents, bactericides, fluid-lossadditives, colorants, and the like. Additives can be added in the formof an additive package, containing various additives.

Dispersants:

Dispersants are generally used to maintain in suspension insolublematerials resulting from oxidation during use, thus preventing sludgeflocculation and precipitation or deposition on engine parts. Examplesof dispersants include nitrogen-containing ashless (metal-free)dispersants. An ashless dispersant generally comprises an oil solublepolymeric hydrocarbon backbone having functional groups that are capableof associating with particles to be dispersed. Other examples ofdispersants include, but are not limited to, amines, alcohols, amides,or ester polar moieties attached to the polymer backbones via bridginggroups.

An ashless dispersant may be selected from oil soluble salts, esters,amino-esters, amides, imides, and oxazolines of long chain hydrocarbonsubstituted mono and dicarboxylic acids or their anhydrides;thiocarboxylate derivatives of long chain hydrocarbons, long chainaliphatic hydrocarbons having a polyamine attached directly thereto; andMannich condensation products formed by condensing a long chainsubstituted phenol with formaldehyde and polyalkylene polyamineCarboxylic dispersants are reaction products of carboxylic acylatingagents (acids, anhydrides, esters, etc.) comprising at least 34 andpreferably at least 54 carbon atoms with nitrogen containing compounds(such as amines), organic hydroxy compounds (such as aliphatic compoundsincluding monohydric and polyhydric alcohols, or aromatic compoundsincluding phenols and naphthols), and/or basic inorganic materials.These reaction products include imides, amides, and esters, e.g.,succinimide dispersants.

Other suitable ashless dispersants may also include amine dispersants,which are reaction products of relatively high molecular weightaliphatic halides and amines, preferably polyalkylene polyamines Otherexamples may further include “Mannich dispersants,” which are reactionproducts of alkyl phenols in which the alkyl group contains at least 30carbon atoms with aldehydes (especially formaldehyde) and amines(especially polyalkylene polyamines). Furthermore, ashless dispersantsmay even include post-treated dispersants, which are obtained byreacting carboxylic, amine or Mannich dispersants with reagents such asdimercaptothiazoles, urea, thiourea, carbon disulfide, aldehydes,ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides,nitrile epoxides, boron compounds and the like. Suitable ashlessdispersants may be polymeric, which are interpolymers ofoil-solubilizing monomers such as decyl methacrylate, vinyl decyl etherand high molecular weight olefins with monomers containing polarsubstitutes. Other suitable ashless dispersants may also include anethylene carbonate-treated bissuccinimide derived from a polyisobutylenehaving a number average molecular weight of about 2300 Daltons (“PIBSA2300”).

Viscosity Index Improvers (Modifiers):

The viscosity index of an engine oil base stock can be increased, orimproved, by incorporating therein certain polymeric materials thatfunction as viscosity modifiers (VM) or viscosity index improvers (VII)in an amount of 0.3 to 25 wt %. of the final weight of the engine oil.Examples include but are not limited to olefin copolymers, such asethylene-propylene copolymers, styrene-isoprene copolymers, hydratedstyrene-isoprene copolymers, polybutene, polyisobutylene,polymethacrylates, vinylpyrrolidone and methacrylate copolymers anddispersant type viscosity index improvers. These viscosity modifiers canoptionally be grafted with grafting materials such as, for example,maleic anhydride, and the grafted material can be reacted with, forexample, amines, amides, nitrogen-containing heterocyclic compounds oralcohol, to form multifunctional viscosity modifiers(dispersant-viscosity modifiers).

Other examples of viscosity modifiers include star polymers (e.g., astar polymer comprising isoprene/styrene/isoprene triblock). Yet otherexamples of viscosity modifiers include poly alkyl(meth)acrylates of lowBrookfield viscosity and high shear stability, functionalized polyalkyl(meth)acrylates with dispersant properties of high Brookfieldviscosity and high shear stability, polyisobutylene having a weightaverage molecular weight ranging from 700 to 2,500 Daltons and mixturesthereof.

Friction Modifiers:

The lubricating oil composition may comprise at least a frictionmodifier (e.g., a sulfur-containing molybdenum compound). Certainsulfur-containing organo-molybdenum compounds are known to modifyfriction in lubricating oil compositions, while also offeringantioxidant and antiwear credits. Examples of oil solubleorgano-molybdenum compounds include molybdenum succinimide complex,dithiocarbamates, dithiophosphates, dithiophosphinates, xanthates,thioxanthates, sulfides, and the like, and mixtures thereof.

Other examples include at least a mono-, di- or triester of a tertiaryhydroxyl amine and a fatty acid as a friction modifying fuel economyadditive. Other examples are selected from the group of succinamic acid,succinimide, and mixtures thereof. Other examples are selected from analiphatic fatty amine, an ether amine, an alkoxylated aliphatic fattyamine, an alkoxylated ether amine, an oil-soluble aliphatic carboxylicacid, a polyol ester, a fatty acid amide, an imidazoline, a tertiaryamine, a hydrocarbyl succinic anhydride or acid reacted with an ammoniaor a primary amine, and mixtures thereof

Seal Swelling Agents:

Seal fixes are also termed seal swelling agents or seal pacifiers. Theyare often employed in lubricant or additive compositions to insureproper elastomer sealing, and prevent premature seal failures andleakages. Seal swell agents may be selected from oil-soluble, saturated,aliphatic, or aromatic hydrocarbon esters such asdi-2-ethylhexylphthalate, mineral oils with aliphatic alcohols such astridecyl alcohol, triphosphite ester in combination with ahydrocarbonyl-substituted phenol, and di-2-ethylhexylsebacate.

Corrosion Inhibitors (Anti-Corrosive Agents):

These additives are typically added to reduce the degradation of themetallic parts contained in the engine oil in amounts from about 0.02 to1 wt %. Examples include zinc dialkyldithiophosphate, phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester. The rust inhibitor or anticorrosion agents may bea nonionic polyoxyethylene surface active agent. Nonionicpolyoxyethylene surface active agents include, but are not limited to,polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether,polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether,polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether,polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitolmono-oleate, and polyethylene glycol monooleate. Rust inhibitors oranticorrosion agents may also be other compounds, which include, forexample, stearic acid and other fatty acids, dicarboxylic acids, metalsoaps, fatty acid amine salts, metal salts of heavy sulfonic acid,partial carboxylic acid ester of polyhydric alcohols, and phosphoricesters. The rust inhibitor may be a calcium stearate salt.

Detergents:

In engine oil compositions, metal-containing or ash-forming detergentsfunction both as detergents to reduce or remove deposits and as acidneutralizers or rust inhibitors, thereby reducing wear and corrosion andextending engine life. Detergents generally comprise a polar head withlong hydrophobic tail, with the polar head comprising a metal salt of anacid organic compound.

The engine oil composition may contain one or more detergents, which arenormally salts (e.g., overbased salts. Overbased salts, or overbasedmaterials), are single phase, homogeneous Newtonian systemscharacterized by a metal content in excess of that which would bepresent according to the stoichiometry of the metal and the particularacidic organic compound reacted with the metal. The engine oilcomposition may comprise at least a carboxylate detergent. Carboxylatedetergents, e.g., salicylates, can be prepared by reacting an aromaticcarboxylic acid with an appropriate metal compound such as an oxide orhydroxide. The engine oil composition may comprise at least an overbaseddetergent. Examples of the overbased detergents include, but are notlimited to calcium sulfonates, calcium phenates, calcium salicylates,calcium stearates and mixtures thereof. Overbased detergents may be lowoverbased (e.g., Total Base Number (TBN) below about 50). Suitableoverbased detergents may alternatively be high overbased (e.g., TBNabove about 150) or medium overbased (e.g., TBN between 50 and 150). Thelubricating oil compositions may comprise more than one overbaseddetergents, which may be all low-TBN detergents, all high-TBNdetergents, or a mix of those two types. Other suitable detergents forthe lubricating oil compositions include “hybrid” detergents such as,for example, phenate/salicylates, sulfonate/phenates,sulfonate/salicylates, sulfonates/phenates/salicylates, and the like.The composition may comprise detergents made from alkyl benzene andfuming sulfonic acid, phenates (high overbased, medium overbased, or lowoverbased), high overbased phenate stearates, phenolates, salicylates,phosphonates, thiophosphonates, sulfonates, carboxylates, ionicsurfactants and sulfonates and the like.

Oxidation Inhibitors/Antioxidants:

Oxidation inhibitors or antioxidants reduce the tendency of mineral oilsto deteriorate in service, which deterioration is evidenced by theproducts of oxidation such as sludge, lacquer, and varnish-like depositson metal surfaces. The engine oil composition may contain from about 50ppm to about 5.00 wt % of at least an antioxidant selected from thegroup of phenolic antioxidants, aminic antioxidants, or a combinationthereof. The amount of antioxidants may be between 0.10 to 3.00 wt %.The amount of antioxidants may be between about 0.20 to 0.80 wt %. Anexample of an antioxidant used is di-C8-diphenylamine, in an amount ofabout 0.05 to 2.00 wt % of the total weight of the oil composition.Other examples of antioxidants include MoS and Mo oxide compounds.

Other examples of antioxidants include hindered phenols; alkaline earthmetal salts of alkylphenolthioesters having C5 to C12 alkyl side chains;calcium nonylphenol sulphide; oil soluble phenates and sulfurizedphenates; phosphosulfurized or sulfurized hydrocarbons or esters;phosphorous esters; metal thiocarbamates; oil soluble copper compoundsknown in the art; phenyl naphthyl amines such as phenylene diamine,phenothiazine, diphenyl amine, diarylamine; phenyl-alphanaphthylamine,2,2′-diethyl-4,4′-dioctyl diphenylamine,2,2′diethyl-4-t-octyldiphenylamine; alkaline earth metal salts ofalkylphenol thioesters, having C5 to C12 alkyl side chains, e.g.,calcium nonylphenol sulfide, barium t-octylphenol sulfide, zincdialkylditbiophosphates, dioctylphenylamine, phenylalphanaphthylamineand mixtures thereof. Some of these antioxidants further function ascorrosion inhibitors. Other suitable antioxidants which also function asantiwear agents include bis alkyl dithiothiadiazoles such as2,5-bis-octyl dithiothiadiazole.

Anti-Foamants:

The engine oil may comprise an anti-foamant (foam inhibitor) in amountsranging from about 5 to about 50 ppm. Examples include alkylmethacrylate polymers, dimethyl silicone polymers, and foam inhibitorsof the polysiloxane type, e.g., silicone oil and polydimethyl siloxane,for foam control. The anti-foamant may be a mixture of polydimethylsiloxane and fluorosilicone. Another example of an anti-foamant may bean acrylate polymer anti-foamant, with a weight ratio of thefluorosilicone antifoamant to the acrylate anti-foamant ranging fromabout 3:1 to about 1:4. Another example of an anti-foamant may be ananti-foam-effective amount of a silicon-containing anti-foamant suchthat the total amount of silicon in the engine oil is at least 30 ppm.The silicon-containing antifoam agent may be selected from the groupconsisting of fluorosilicones, polydimethylsiloxane, phenyl-methylpolysiloxane, linear siloxanes, cyclic siloxanes, branched siloxanes,silicone polymers and copolymers, organo-silicone copolymers, andmixtures thereof.

Anti-Wear Agents:

Anti-wear agents can also be added to the engine oil composition. Thecomposition may comprise at least an anti-wear agent selected fromphosphates, phosphites, carbamates, esters, sulfur containing compounds,and molybdenum complexes. Other representative of suitable antiwearagents are zinc dialkyldithiophosphate, zinc diaryldilhiophosphate, Znor Mo dithiocarbamates, phosphites, amine phosphates, boratedsuccinimide, magnesium sulfonate, and mixtures thereof. The compositionmay comprise at least a dihydrocarbyl dithiophosphate metal as antiwearand antioxidant agent in amounts of about 0.1 to about 10 wt %. Themetal may be an alkali or alkaline earth metal, or aluminum, lead, tin,molybdenum, manganese, nickel or copper.

Extreme Pressure Agents:

The engine oil composition may comprise an extreme pressure agent.Examples include alkaline earth metal borated extreme pressure agentsand alkali metal borated extreme pressure agents. Other examples includesulfurized olefins, zinc dialky-1-dithiophosphate (primary alkyl,secondary alkyl, and aryl type), di-phenyl sulfide, methyltri-chlorostearate, chlorinated naphthalene, fluoroalkylpolysiloxane,lead naphthenate, neutralized or partially neutralized phosphates,di-thiophosphates, and sulfur-free phosphates.

Some of the above-mentioned additives can provide a multiplicity ofeffects; thus for example, a single additive may act as a dispersant aswell as an oxidation inhibitor. These multifunctional additives are wellknown. Furthermore, when the engine oil composition contains one or moreof the above-mentioned additives, each additive is typically blendedinto the base oil in an amount that enables the additive to provide itsdesired function. It may be desirable, although not essential to prepareone or more additive concentrates comprising additives (concentratessometimes being referred to as “additive packages”) whereby severaladditives can be added simultaneously to the oil to form the end oilcomposition. The final composition may employ from about 0.5 to about 30wt % of the concentrate, the remainder being the oil of lubricatingviscosity. The components can be blended in any order and can be blendedas combinations of components.

DEFINITIONS AND TERMS

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

The phrase “Group I Base Oil” contain less than 90 percent saturatesand/or greater than 0.03 percent sulfur and have a viscosity indexgreater than or equal to 80 and less than 120 using the ASTM methodsspecified in Table E-1 of American Petroleum Institute Publication 1509.

The term “Group II Base Oil” refers to a base oil which contains greaterthan or equal to 90% saturates and less than or equal to 0.03% sulfurand has a viscosity index greater than or equal to 80 and less than 120using the ASTM methods specified in Table E-1 of American PetroleumInstitute Publication 1509.

The term “Group II+ Base Oil” refers to a Group II base oil having aviscosity index greater than or equal to 110 and less than 120.

The term “Group III Base Oil” refers to a base oil which containsgreater than or equal to 90% saturates and less than or equal to 0.03%sulfur and has a viscosity index greater than or equal to 120 using theASTM methods specified in Table E-1 of American Petroleum InstitutePublication 1509.

The term “Fischer-Tropsch derived” means that the product, fraction, orfeed originates from or is produced at some stage by a Fischer-Tropschprocess.

The term “petroleum derived” means that the product, fraction, or feedoriginates from the vapor overhead streams from distilling petroleumcrude and the residual fuels that are the non-vaporizable remainingportion. A source of the petroleum derived product, fraction, or feedcan be from a gas field condensate.

The term “multi-grade engine oil” refers to an engine oil that hasviscosity/temperature characteristics which fall within the limits oftwo different SAE numbers in SAE J300. The present invention is directedto the discovery that multi-grade engine oils meeting the specificationsunder SAE J300 as revised 2009, including the MRV viscosityspecifications, may be prepared from Fischer-Tropsch base oils having adefined cycloparaffin functionality when they are blended with a pourpoint depressing base oil blending component and an additive package.

The term “light neutral base oil” refers to a base oil with a boilingrange from about 700° F. to about 800° F., a kinematic viscosity at 100°C. from 4 cSt to about 5 cSt.

The term “medium neutral base oil” refers to a base oil with a boilingrange from about 800° F. to about 900° F., a kinematic viscosity at 100°C. from 5 cSt to about 8 cSt.

Highly paraffinic wax means a wax having a high content of n-paraffins,generally greater than 40 wt %, but can be greater than 50 wt %, or evengreater than 75 wt %, and less than 100 wt % or 99 wt %. Examples ofhighly paraffinic waxes include slack waxes, deoiled slack waxes,refined foots oils, waxy lubricant raffinates, n-paraffin waxes, NAOwaxes, waxes produced in chemical plant processes, deoiled petroleumderived waxes, microcrystalline waxes, Fischer-Tropsch waxes, andmixtures thereof.

The term “derived from highly paraffinic wax” means that the product,fraction, or feed originates from or is produced at some stage by from ahighly paraffinic wax.

Aromatics means any hydrocarbonaceous compounds that contain at leastone group of atoms that share an uninterrupted cloud of delocalizedelectrons, where the number of delocalized electrons in the group ofatoms corresponds to a solution to the Huckel rule of 4n+2 (e.g., n=1for 6 electrons, etc.). Representative examples include, but are notlimited to, benzene, biphenyl, naphthalene, and the like.

Molecules with cycloparaffinic functionality mean any molecule that is,or contains as one or more substituents, a monocyclic or a fusedmulticyclic saturated hydrocarbon group. The cycloparaffinic group canbe optionally substituted with one or more, such as one to three,substituents. Representative examples include, but are not limited to,cyclopropyl, cyclobutyl, cyclohexyl, cyclopentyl, cycloheptyl,decahydronaphthalene, octahydropentalene, (pentadecan-6-yl)cyclohexane,3,7,10-tricyclohexylpentadecane,decahydro-1-(pentadecan-6-yl)naphthalene, and the like.

Molecules with monocycloparaffinic functionality mean any molecule thatis a monocyclic saturated hydrocarbon group of three to seven ringcarbons or any molecule that is substituted with a single monocyclicsaturated hydrocarbon group of three to seven ring carbons. Thecycloparaffinic group can be optionally substituted with one or more,such as one to three, substituents. Representative examples include, butare not limited to, cyclopropyl, cyclobutyl, cyclohexyl, cyclopentyl,cycloheptyl, (pentadecan-6-yl)cyclohexane, and the like.

Molecules with multicycloparaffinic functionality mean any molecule thatis a fused multicyclic saturated hydrocarbon ring group of two or morefused rings, any molecule that is substituted with one or more fusedmulticyclic saturated hydrocarbon ring groups of two or more fusedrings, or any molecule that is substituted with more than one monocyclicsaturated hydrocarbon group of three to seven ring carbons. The fusedmulticyclic saturated hydrocarbon ring group often is of two fusedrings. The cycloparaffinic group can be optionally substituted with oneor more, such as one to three, substituents. Representative examplesinclude, but are not limited to, decahydronaphthalene,octahydropentalene, 3,7,10-tricyclohexylpentadecane,decahydro-1-(pentadecan-6-yl)naphthalene, and the like.

Brookfield Viscosity: ASTM D2983-04a is used to determine thelow-shear-rate viscosity of automotive fluid lubricants at lowtemperatures. The low-temperature, low-shear-rate viscosity of automatictransmission fluids, gear oils, torque and tractor fluids, andindustrial and automotive hydraulic oils are frequently specified byBrookfield viscosities.

Kinematic viscosity is a measurement of the resistance to flow of afluid under gravity. Many base oils, lubricant compositions made fromthem, and the correct operation of equipment depends upon theappropriate viscosity of the fluid being used. Kinematic viscosity isdetermined by ASTM D445-06. The results are reported in mm²/s.

Viscosity index (VI) is an empirical, unitless number indicating theeffect of temperature change on the kinematic viscosity of the oil.Viscosity index is determined by ASTM D2270-04.

Pour point is a measurement of the temperature at which a sample of baseoil will begin to flow under carefully controlled conditions. Pour pointcan be determined as described in ASTM D5950-02. The results arereported in degrees Celsius. Many commercial base oils havespecifications for pour point. When base oils have low pour points, thebase oils are also likely to have other good low temperature properties,such as low cloud point, low cold filter plugging point, and lowtemperature cranking viscosity.

Noack volatility is usually tested according to ASTM D5800-05 ProcedureB. A more convenient method for calculating Noack volatility and onewhich correlates well with ASTM D5800-05 is by using a thermogravimetricanalyzer (TGA) test by ASTM D6375-05. TGA Noack volatility is usedthroughout the present disclosure unless otherwise stated.

The base oils of the lubricant composition as disclosed herein also haveexcellent viscometric properties under low temperature (i.e., cold flowproperties) and high shear, making them very useful in multi-gradeengine oils. The cold-cranking simulator apparent viscosity (CCS VIS) isa test used to measure the viscometric properties of base oils under lowtemperature and high shear. The test method to determine CCS VIS is ASTMD5293-02. Results are reported in mPa·s. CCS VIS has been found tocorrelate with low temperature engine cranking. Specifications formaximum CCS VIS are defined for automotive engine oils by SAE J300,revised in 2009. The maximum CCS VIS for a 0W SAE Viscosity Grade engineoil is 6200 mPa·s at −35° C.

The phrase “improving cold flow properties” refers to one or more oflowering CCS VIS (cold-cranking simulator apparent viscosity) at −25°C., −30° C. or −35° C., lowering pour point and lowering Noack.

The Mini-Rotary Viscometer (MRV) test, ASTM D4684-07, which is relatedto the mechanism of pumpability, is a low shear rate measurement. Slowsample cooling rate is the method's key feature. A sample is pretreatedto have a specified thermal history which includes warming, slowcooling, and soaking cycles. The MRV measures an apparent yield stress,which, if greater than a threshold value, indicates a potentialair-binding pumping failure problem. Above a certain viscosity(currently defined as 60,000 mPa·s by SAE J300 2009), the oil may besubject to pumpability failure by a mechanism called “flow limited”behavior. An SAE 0W oil, for example, is required to have a maximumviscosity of 60,000 mPa·s at −40° C. with no yield stress. This methodalso measures an apparent viscosity under shear rates of 1 to 50 s⁻¹.

High temperature high shear rate viscosity (HTHS) is a measure of afluid's resistance to flow under conditions resembling highly-loadedjournal bearings in fired internal combustion engines, typically 1million s⁻¹ at 150° C. HTHS is a better indication of how an engineoperates at high temperature with a given lubricant than the kinematiclow shear rate viscosities at 100° C. The HTHS value directly correlatesto the oil film thickness in a bearing. SAE J300 2009 contains thecurrent specifications for HTHS measured by ASTM D4683, ASTM D4741, orASTM D5481. An SAE 20 viscosity grade engine oil, for example, isrequired to have a minimum HTHS of 2.6 mPa·s.

Scanning Brookfield Viscosity: ASTM D5133-05 is used to measure the lowtemperature, low shear rate, viscosity/temperature dependence of engineoils. The low temperature, low shear viscometric behavior of an engineoil determines whether the oil will flow to the sump inlet screen, thento the oil pump, then to the sites in the engine requiring lubricationin sufficient quantity to prevent engine damage immediately orultimately after cold temperature starting. ASTM D5133-05, the ScanningBrookfield Viscosity technique, measures the Brookfield viscosity of asample as it is cooled at a constant rate of 1° C./hour. Like the MRV,ASTM D5133-05 is intended to relate to the pumpability of an oil at lowtemperatures. The test reports the gelation point, defined as thetemperature at which the sample reaches 30,000 mPa·s. The gelation indexis also reported, and is defined as the largest rate of change ofviscosity increase from −5° C. to the lowest test temperature. Thelatest API SM/ILSAC GF-4 specifications for passenger car engine oilsrequire a maximum gelation index of 12.

“Lubricants,” as defined herein, are substances (usually a fluid underoperating conditions) introduced between two moving surfaces so toreduce the friction and wear between them. Base oils used as motor oilsare generally classified by the American Petroleum Institute as beingmineral oils (Group I, II, and III) or synthetic oils (Group IV and V).See American Petroleum Institute (API) Publication Number 1509.

“Pour point,” as defined herein, represents the lowest temperature atwhich a fluid will pour or flow. See, e.g., ASTM International StandardTest Methods D 5950-96, D 6892-03, and D 97.

“Cloud point,” as defined herein, represents the temperature at which afluid begins to phase separate due to crystal formation. See, e.g., ASTMStandard Test Methods D 5773-95, D 2500, D 5551, and D 5771.

“Centistoke,” abbreviated “cSt,” is a unit for kinematic viscosity of afluid (e.g., a lubricant), wherein 1 centistoke equals 1 millimetersquared per second (1 cSt=1 mm²/s). See, e.g., ASTM Standard Guide andTest Methods D 2270-04, D 445-06, D 6074, and D 2983.

With respect to describing molecules and/or molecular fragments herein,“R_(n),” where “n” is an index, refers to a hydrocarbon group, whereinthe molecules and/or molecular fragments can be linear and/or branched.

As defined herein, “C_(n),” where “n” is an integer, describes ahydrocarbon molecule or fragment (e.g., an alkyl group) wherein “n”denotes the number of carbon atoms in the fragment or molecule.

The prefix “bio,” as used herein, refers to an association with arenewable resource of biological origin, such as resource generallybeing exclusive of fossil fuels.

The term “internal olefin,” as used herein, refers to an olefin (i.e.,an alkene) having a non-terminal carbon-carbon double bond (C═C). Thisis in contrast to “α-olefins” which do bear a terminal carbon-carbondouble bond.

The terms Yubase 4 and Yubase 6 are base oils defined as presented inTable 1 shown below.

TABLE 1 Property Test Method YUBASE 4 YUBASE 6 Appearance Visual Bright& Clear Bright & Clear Specific Gravity, ASTM D 1298 0.8338 0.8423@15/4° C. Kinematic Viscosity, ASTM D 445 19.57 36.82 @40° C. KinematicViscosity, ASTM D 445 4.23 6.52 @100° C. Viscosity Index ASTM D 2270 122131 Noack Volatility, wt % DIN 51581 15 7 Flash Point, ° C. ASTM D 92230 240 Pour Point, ° C. ASTM D 97 −15 −15 Color ASTM D 1500 L0.5 L0.5Con. Carbon Residue, ASTM D 189 <0.01 <0.01 wt % Copper Corrosion ASTM D130 1-a 1-a Sulfur, ppm ASTM D 2622 <10 <10 Total Acid No., ASTM D 6640.01 0.01 mgKOH/g

The terms “100R, 150R, 220R, 600R and 110RLV” are base oils defined aspresented in Table 2 shown below.

TABLE 2 Property ASTM Method 100R 150R 220R 600R 110RLV API Base OilCategory API 1509 E 1.3 II II II II II(+) Appearance SM 360-99 BrightBright Bright Bright Bright and Clear and Clear and Clear and Clear andClear Color ASTM D 1500 L0.5 L0.5 L0.5 L0.5 L0.5 API Gravity, deg. ASTMD 4052 34.4 33.4 31.9 31.2 35.4 Density, lb/gal ASTM D 4052 7.1 7.157.22 7.28 7.06 Density, kg/l ASTM D 4052 0.853 0.858 0.867 0.874 0.848Specific Gravity, @ ASTM D 4052 0.853 0.858 0.867 0.874 0.848 60° F./60°F. Viscosity @ 40° C., cSt ASTM D 445 20.3 30.9 43.7 108 21.1 Viscosity@ 100° C., cSt ASTM D 445 4.1 5.3 6.6 12.2 4.4 Viscosity @ 100° F., SUSASTM D 2161 107 153 214 590 113 Viscosity Index ASTM D 2270 102 107 102103 118 CCS @ −20° C., cP ASTM D 5293 N/A 1750 3400 N/A 822 CCS @ −25°C., cP ASTM D 5293 1400 2660 5600 N/A 1350 CCS @ −30° C., cP ASTM D 52932650 5070 N/A N/A 2450 Pour Point, ° C. ASTM D 5950/1C −15 −15 −13 −17−15 Flash Point, COC, ° C. ASTM D 92 206 227 230 270 216 Volatility, wt.% distilled ASTM D 2887 13 N/A N/A N/A N/A at 700° F./371° C.Evaporative Loss, ASTM D5800 (B) 26 14 10 2 16 NOACK, wt % Water, ppmASTM D 6304-98 <50 <50 <50 <50 <50 Sulfur, ppm ICP/XRF <10 <10 <10 <10<6 Saturates, HPLC wt. % Chevron >99 >99 >99 >99 >99 Aromatics, HPLC wt.% Chevron <1 <1 <1 <1 <1

Unless otherwise indicated herein, scientific and technical terms usedin connection with the present invention shall have the meanings thatare commonly understood by those of ordinary skill in the art. Further,unless otherwise required by context, singular terms shall includepluralities and plural terms shall include the singular. Morespecifically, as used in this specification and the appended claims, thesingular forms “a”, “an” and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “afatty acid” includes a plurality of fatty acids, and the like. Inaddition, ranges provided in the specification and appended claimsinclude both end points and all points between the end points.Therefore, a range of 2.0 to 3.0 includes 2.0, 3.0 and all pointsbetween 2.0 and 3.0. Furthermore, all numbers expressing quantities,percentages or proportions, and other numerical values used in thespecification and claims, are to be understood as being modified in allinstances by the term “about”. As used herein, the term “include” andits grammatical variants are intended to be non-limiting, such thatrecitation of items in a list is not to the exclusion of other likeitems that can be substituted or added to the listed items. As usedherein, the term “comprising” means including elements or steps that areidentified following that term, but any such elements or steps are notexhaustive, and an embodiment can include other elements or steps.

EXAMPLES

The following examples are provided to demonstrate particularembodiments of the present invention. It should be appreciated by thoseof skill in the art that the methods disclosed in the examples whichfollow merely represent exemplary embodiments of the present invention.However, those of skill in the art should, in light of the presentdisclosure, appreciate that many changes can be made in the specificembodiments described and still obtain a like or similar result withoutdeparting from the spirit and scope of the present invention.

Example 1

This example serves to illustrate the base oil blends with and withoutthe diesters of the present invention with the analytics presented inTable 3 below.

The diester-free base oil blend was prepared by mixing 82.67 wt % Yubase4 and 17.33 wt % Yubase 6. The base oil component with diester wasprepared by mixing 69.7 wt % Yubase 4, 13.8 wt % Yubase 6, and 16.5 wt %diester of Formula I wherein R₁ and R₂ are combined to have a carbonnumber of C₁₂ and R₃ and R₄ are both C₁₂. Both samples were submittedfor standard base oil testing, including API gravity, viscosity at 40°C. and 100° C., Viscosity Index, pour point, cloud point, Noackvolatility, cold cranking viscosity, and Bromine number.

TABLE 3 Base Oil Blend Example 1 Diester A, wt % 0 16.5 Yubase 4, wt %82.67 69.7 Yubase 6, wt % 17.33 13.8 Properties API 42.5 36.2 Vis @ 100°C., cSt 4.515 4.523 VI 130 132 Pour point, ° C. −14 −17 Cloud point, °C. −10 −12 Noack, wt % 12.65 12.46 CCS @ −35° C., cP 3225 2928 Brominenumber 0.1 0.08

Example 2

This example serves to illustrate the base oil blends with the diestersof the present invention, a single comparative without diester and asecond comparative with a commercially available ester (i.e., EsterexA51) with the analytics presented in Table 4 below. Diester A is adiester of Formula I, wherein R₁ and R₂ are combined to have a carbonnumber of C₁₂ and R₃ and R₄ are both C₁₂. Diester B2 is a diester ofFormula I, wherein R₁ and R₂ are combined to have a carbon number of C₁₂and R₃ and R₄ are both independently C₆-C₁₀. The examples in Table 3were prepared in a similar manner as those of Example 1 herein.

TABLE 4 Composition, wt % BOB02958 BOB02959 BOB02960 BOB02961 110RLV52.43 59.31 59.25 59.16 100R 13.01 220R 34.56 35.55 35.51 35.46 DiesterA 5.14 Diester B2 5.24 Esterex A51 5.37 BOB Properties, CalculatedKV100, centistokes 4.988 5.07 5.044 5.103 KV40, centistokes 26.76 27.0627.03 27.46 VI 112 115 114 115 CCS, cP @ −25° C. 2137 2103 2120 2164CCS, cP @ −30° C. 3929 3840 3880 3961 Noack volatility, % wt loss 14.8BOB Properties, Observed KV100, centistokes 4.971 5.002 4.975 5.047KV40, centistokes 26.51 26.35 26.27 26.73 VI 113 117 115 117 CCS, cP @−25° C. 2165 1952 1972 2084 CCS, cP @ −30° C. 3912 3513 3529 3751 Noack,wt % 14.2 13.4 13.9 13.1

Example 3

This example serves to illustrate the diesters prepared and theirrespective properties as presented in Table 5.

TABLE 5 Properties Starting Materials Cloud Pour Viscosity ViscosityViscosity Oxidator NOACK, No. Olefins Fatty Acids Point Point (40° C.)(100° C.) Index BN wt % loss A C14 C12 −28 −27  19.5 cSt  4.76 cSt 17626 hrs 8.9 B B1 C14 C6(high)-C10 −69 −66 16.41 cSt  3.68 cSt 109 19.3hrs  — B2 C14 C6(low)-C10 −60 −60 19.47 cSt 4.191 cSt 120 26.25 hrs  9.1 C C16 C12 −18 −19 24.44 cSt 5.218 cSt 152 38 hrs E C18 C6-C10 −24−26  20.4 cSt  4.5 cSt 137 25.5 D D1 C16 C6(high)-C10 −51 −51 17.90 cSt4.015 cSt 124 — — D2 C16 C6(low)-C10 −51 −53 21.54 cSt 4.545 cSt 128 26hrs 6.3

Example 4

This example serves to illustrate the Noack and CCS Viscosity of thediesters of the present invention as compared to the current commercialesters and other Group II and III bases oils as presented in Table 6 andFIG. 1.

TABLE 6 Sample CCS (−25) CCS (−30) Noack KV100 Diester A 542 812 8.94.76 Diester B2 1002 1717 9.1 4.19 Diester D2 1104 1875 6.3 4.545Esterex A51 1468 2487 7.4 5.4 Esterex A32 212 319 30.3 2.8

All patents, patent applications and publications are hereinincorporated by reference to the same extent as if each individualpatent, patent application or publication was specifically andindividually indicated to be incorporated by reference.

The present invention if not to be limited in scope by the specificembodiments described herein, which are intended as single illustrationsof individual aspects of the invention, and functionally equivalentmethods and components are within the scope of the invention. Indeed,various modifications of the invention, in addition to those shown anddescribed herein will become apparent to those skilled in the art fromthe foregoing description and accompanying drawings. Such modificationsare intended to fall within the scope of the appended claims.

What is claimed is:
 1. A multi-grade engine oil comprising: a) a diestercomponent, comprising a quantity of at least one diester species havingthe following structure:

wherein R₁, R₂, R₃ and R₄ are the same or independently selected from C₂to C₁₇ hydrocarbon groups; b) a second base oil; and c) an additivepackage, wherein the second base and third base oil are independentlyselected from the group consisting of Group I base oil, Group II baseoil or Group III base oil.
 2. The multi-grade engine oil of claim 1,wherein a quantity of at least one diester species comprises a mixtureof isomers where R₁ and R₂ are different for each isomer.
 3. Themulti-grade engine oil of claim 1, further comprising, a third base oil.4. The multi-grade engine oil of claim 1, wherein the diester has aNoack Volatility between about 6 and 10 wt %, a CCS Viscosity at −30° C.between about 700 and 2000 cP, a pour point less than about −10° C., acloud point less than about −10° C., a kinematic viscosity at 100° C.between about 2.5 to 6.5 centistokes, a VI greater than about 110 and aBN Oxidator greater than about 20 hours.
 5. The multi-grade engine oilaccording to claim 1 or 3, wherein the second base and third base oilare independently selected from the group consisting of light neutralbase oil, medium neutral base oil, Yubase 4, Yubase 6, 150R, 600R,110RLV, 220R and 100R.
 6. The multi-grade engine oil of claim 1, meetingthe specifications for SAE viscosity grade 0W-XX or 5W-XX, wherein XXrepresents the integer 16, 20, 30, or
 40. 7. The multi-grade engine oilof claim 1, wherein the multi-grade engine oil meets the SAE J300standards as revised in January
 2009. 8. The multi-grade engine oil ofclaim 1, having: a) a viscosity index between about 140-200; b) akinematic viscosity at 100° C. between about 6-10 cSt; c) a Pour Pointless than about −30° C.; and d) a Noack volatility of less than about 15wt %, wherein the multi-grade engine oil is a 0W-SAE grade with a CCSViscosity at −35° C. less than about 6200 cP or the multi-grade engineoil is a 5W-SAE grade with a CCS Viscosity at −30° C. less than about6600 cP.
 9. The multi-grade engine oil of claim 1, wherein the kinematicviscosity of the multi-grade engine oil at a temperature of 100° C. isbetween about 3 to 10 centistokes.
 10. The multi-grade engine oil ofclaim 1, wherein the CCS Viscosity at −30° C. less than about 6,600 cP.11. The multi-grade engine oil of claim 1, wherein the CCS Viscosity at−35° C. less than about 6,200 cP.
 12. The multi-grade engine oil ofclaim 1, wherein the Noack Volatility less than about 15 wt %.
 13. Themulti-grade engine oil of claim 1, wherein R₁ and R₂ are selected tohave a combined carbon number of from 6 to 16 and R₃ and R₄ are selectedto have a combined carbon number of from 10 to
 34. 14. The multi-gradeengine oil of claim 1, wherein R₁ and R₂ of Formula I are selected tohave a combined carbon number of C₁₆, C₁₄ or C₁₂ and R₃ and R₄ areindependently selected from the group consisting of C₁₂ and a mixture ofC₆-C₁₀.
 15. The multi-grade engine oil of claim 1, wherein the at leastone diester species is derived from a C₈ to C₁₈ olefin and a C₆ to C₁₄carboxylic acid.
 16. The multi-grade engine oil of claim 2, wherein saidcomposition comprises quantities of at least two different diesterisomers.
 17. The multi-grade engine oil of claim 1, wherein the at leastone diester species has a molecular mass that is from at least about 340a.m.u. to at most about 780 a.m.u.
 18. The multi-grade engine oil ofclaim 1, wherein the at least one diester species is selected from thegroup consisting of decanoic acid 2-decanoyloxy-1-hexyl-octyl ester andits isomers, tetradecanoic acid-1-hexyl-2-tetradecanoyloxy-octyl estersand its isomers, dodecanoic acid 2-dodecanoyloxy-1-hexyl-octyl ester andits isomers, hexanoic acid 2-hexanoyloxy-1-hexy-octyl ester and itsisomers, octanoic acid 2-octanoyloxy-1-hexyl-octyl ester and itsisomers, hexanoic acid 2-hexanoyloxy-1-pentyl-heptyl ester and isomers,octanoic acid 2-octanoyloxy-1-pentyl-heptyl ester and isomers, decanoicacid 2-decanoyloxy-1-pentyl-heptyl ester and isomers, decanoicacid-2-cecanoyloxy-1-pentyl-heptyl ester and its isomers, dodecanoicacid-2-dodecanoyloxy-1-pentyl-heptyl ester and isomers, tetradecanoicacid 1-penty-2-tetradecanoyloxy-heptyl ester and isomers, tetradecanoicacid 1-butyl-2-tetradecanoyloxy-hexy ester and isomers, dodecanoicacid-1-butyl-2-dodecanoyloxy-hexyl ester and isomers, decanoic acid1-butyl-2-decanoyloxy-hexyl ester and isomers, octanoic acid1-butyl-2-octanoyloxy-hexyl ester and isomers, hexanoic acid1-butyl-2-hexanoyloxy-hexyl ester and isomers, tetradecanoic acid1-propyl-2-tetradecanoyloxy-pentyl ester and isomers, dodecanoic acid2-dodecanoyloxy-1-propyl-pentyl ester and isomers, decanoic acid2-decanoyloxy-1-propyl-pentyl ester and isomers, octanoic acid1-2-octanoyloxy-1-propyl-pentyl ester and isomers, hexanoic acid2-hexanoyloxy-1-propyl-pentyl ester and isomers, and mixtures thereof.19. The multi-grade engine oil of claim 1, wherein the multi-gradeengine oil is formulated as a 0W-20 SAE 0W-16 or 5W-20 SAE engine oil.